1. Field of the Invention
The present invention relates to a high-strength/high-elongation magnesium alloy for room temperature, and a manufacturing method thereof.
2. Description of the Prior Art
Currently, Mg—Al based alloys are widely used in industries. When aluminum (Al) is added into a magnesium (Mg) alloy, the strength of the Mg alloy is increased, the melting point is lowered, and flowability is improved because of solid-solution strengthening due to Al and grain boundary strengthening due to the formation of β-Mg17Al12 phase. Therefore, Mg alloys with Al added are suitable for die casting applications. However, ductility is deteriorated due to the increase in β phases which are highly brittle. To apply magnesium alloys to automobile parts, magnesium alloys should not be broken at once but endure an impact by absorbing impact energy even if the impact is exerted thereon. For this reason, magnesium alloys should have high ductility at room temperature. Improvement of ductility makes it possible to secure processability and product moldability as well.
Therefore, to secure the strength and castability of magnesium alloys, it is necessary to develop Mg—Al based alloys having high ductility in which an addition ratio of Al should be maintained to a predetermined level or more. In general, increasing ductility is in trade-off relation to strength. If an increase in ductility leads to a decrease in strength, this also provides a limitation to application fields of alloys and it is thus difficult to commercialize Mg alloys.
Accordingly, the ductility and strength should be considered at the same time. To improve the ductility of Mg—Al alloys, the formation of highly brittle β phases should be suppressed by forming a new phase through addition of elements which are highly reactive with Mg or Al.